I guess it all depend on where you shop for fuel. In an unknown area I would stick to places that are busy, and not necessarily cheap either. 85% of the time I will pump a gallon and sniff the nozzle. Why? because diesel smells a lot different then gas. Also avoid going to stations with a delivery truck parked outside. give that fuel time to settle in the underground tanks.
In Mexico, the prices are controlled by the government, actually, the gas stations(Pemex) are governed by the governent but owned by franchisers. So for me price isn't the determining factor.
I try to always go to the busy stations, but when you are 100 miles from the closest station in the middle nowhere on some adventure, the guy with the 50 gallon drum of fuel is the only option!
Also, whatever fuel filtration system you decide on, make it:
1- easy to service. A .01 micron filter inside the tank is NOT easy to service.
2- carry spares. I carry at least one spare in my truck. Remember, a fuel filter can last 10,000 miles or 10 miles. It all depends on how much crud is in the fuel. Like a chain saw - can cut up a whole tree or you can cut one branch, bury it in the dirt and then it couldnt cut butter on a summer day.
3- consider mounting 2 or more filters in "parallel". And have only one running at a time. So if filter "A" gets clogged up, you can switch to filter "B" and roll on to a more convenient or safer place to change the filter.
4- get a good gauge(s) to monitor the filters. I have two gauges, because I just have the one filter; mounted before and after the filter head. It is a sure way to diagnose the problem. If the prefilter gauge is reading 4 psi and the after is reading 2, I know its about time for a new filter. If both gauges are reading one psi, I know that either I am sucking air or the lift pump has gone. Some gauges like racor have vacuum gauges on them to keep tabs on the filter.
From what I have going in my head:
1. A water/fuel seperator down line from the lift pump on the motor, location still being located! Right now I'm sitting on a Cummins filter head and a Cummins Fuel/water seperator.
2. The fuel filter on the motor(My 7.3 has a 6.9 head which after hours of searching, only has a fuel filter available for it, no seperator.
3. I have spares of each already purchased and in my box o' goodies in my camper. I know also have an extra lift pump and pretty soon an injector pump.)
4. Was considering a fuel pressure gauge, where should I put it to give me the best indication of a fuel problem?[/QUOTE]
If you are really that concerned, then I would buy a 100 gallon reserve tank. I would fill up that tank with fuel from a truck stop. In mexico I would use only the factory tanks and then If you had a big problem with contaminated fuel (such as you got semi-gloss rustoleum primer instead of diesel), You could change the filters and use the good ol USLD to get home.
Unfortunately I have a pop up camper on the truck full time so that's a no go. Was considering purchasing the tanks that fit in the wheel well.
In actuality the mexican fuel is probably high sulfer, so the old girl will run 10 times better. I would go to mexico just to buy the fuel.
From what I've heard, they are between 300-500 parts per million.. Since I bought the truck in 06, it's probably only seen about 8k worth of U.S. fuel in the 20k I've driven it.